Hi,

This is a built-in tool from Odoo and it makes it possible to translate text in multiple languages.
Imagine that you want to show a warning to a user when something is wrong. Then you would do something like this:

raise ValidationError('At least one language must be active.')

This will work fine but what if you have one user in your system that is English and one that is Dutch? Well, both would get it in English in this case. When you use the "_" import from Odoo you'll be able to make the text translatable. Your code would look like this then:

raise ValidationError(_('At least one language must be active.'))

By using _() in the code it will be parsed by Odoo. If you then export your translations this string will be in the text values too and you'll be able to translate it in any language that you'd like.

See this: https://www.odoo.com/forum/help-1/question/what-is-the-meaning-of-the-underscore-in-the-python-odoo-import-statement-129061

Thanks